3D positioning system using magnetic field

A method to determine the 3D position using harmless magnetic field is proposed as a solution to the problem of positioning the medical instruments such as endoscope inside the patient's body. The intension expression of magnetic induction produced by a single loop coil is derived and the mathematical model of 3D positioning system with a mode of magnetic field is established. Then a practical 3D positioning system is developed to implement real-time 6 degrees of freedom measurement by a 3D magnetic sensor attached to the endoscope and 5 degrees measurement by a single magnetic sensor.